Thyroid nodules are commonly encountered in clinical practice. They are present in 4 to 7% of the population by neck palpation and 30 to 50% by ultrasonography. Most are benign and could be neglected by ... [more ▼]

Thyroid nodules are commonly encountered in clinical practice. They are present in 4 to 7% of the population by neck palpation and 30 to 50% by ultrasonography. Most are benign and could be neglected by the clinician and his patient. However, 5% of nodules are malignant, requiring surgical treatment; therefore, an exhaustive evaluation is needed. The diagnostic approach includes physical examination, laboratory analysis, ultrasonography, radioisotope imaging, and fine needle aspiration. This article, based on the literature and the authors'experience, provides recommandations for thyroid nodule management. [less ▲]

The medical records of nine patients (five female and four male, mean age 58 +/- 5 years) presenting with a carotid chemodectoma between 1983 and 1995 were reviewed. In two cases (22%) the diagnostic was ... [more ▼]

The medical records of nine patients (five female and four male, mean age 58 +/- 5 years) presenting with a carotid chemodectoma between 1983 and 1995 were reviewed. In two cases (22%) the diagnostic was not suspected at the time of initial presentation. The most common complaint was a swelling in the anterolateral region of the neck. One patient (11%) presented with a preoperative peripheral nerves deficits (vagus and hypoglossal palsies and Horner's syndrome). Two tumours were embolized preoperatively with polyvinyl alcohol particles. Complete surgical excision was possible in each patient and the plane of resection was adventitial. In three cases, early ligation of the external carotid artery facilitated the resection. In two patients, the vagus nerve was sacrificed because of tumour involvement. No operative mortality was observed and no vascular complication occurred. In addition to the patient with preoperative neurologic symptoms, three patients developed peripheral nerve deficits (vagus and hypoglossal nerves) postoperatively. Two of these deficits were transient. These peripheral neurologic complications were observed with the largest tumour sizes. Two cases were malignant (lymph nodes and bony metastases). These two patients received postoperative radiotherapy. The mean follow-up period 63 +/- 19 months. No patient developed local recurrence during the follow-up. Two patients died during the follow-up, one for condition unrelated to their disease and the second from metastatic dissemination. In conclusion, carotid chemodectomas may be safely resected. The best way to minimize the rate of complications is to operate them at an early stage of evolution. [less ▲]

Radiation-induced thymic lymphomas in C57Bl/Ka mice are interesting models for studying the successive steps of carcinogenesis. Irradiation initiates "preleukemic" cells, which are promoted to become ... [more ▼]

Radiation-induced thymic lymphomas in C57Bl/Ka mice are interesting models for studying the successive steps of carcinogenesis. Irradiation initiates "preleukemic" cells, which are promoted to become neoplastic. Studies in mice in which lymphoma development is inhibited by a bone marrow transplantation after irradiation suggest that radiation--induced alterations to the T cell lineage, and particularly to thymic microenvironment, are critical for the promotion of preleukemic cells. It is proposed that the lack of physiological differentiation signals within the thymus, as a result of irradiation, allows these cells to escape the normal controls of thymocyte production and pushes them towards neoplastic transformation. A disturbance in the production of cytokines may be involved, since exogenous cytokines, such as Interferon gamma or Tumor Necrosis Factor a, can inhibit radiation-induced lymphomagenesis, reproducing the effects of bone marrow transplantation. The model is thus suitable for studying the mechanisms of carcinogenesis and designing biological manipulation devoted to cancer prevention in individuals who have been exposed to oncogenic agents. [less ▲]